DevTeam says that 2.2 update SHOULD NOT be applied using iTunes if you want the chance of a soft-unlock in the near future. Use new version of PwnageTool (not avaliable yet, but will be soon).
Some fact:
The 2.2 firmware for 3G contains a baseband update for the 3G iPhone
The 2.2 firmware for 2G (1st gen iPhones) doesn’t contain a baseband update and the baseband is still at 04.05.04
Pwnage technique (and therefore the Jailbreak) isn’t affected, but PwnageTool and QuickPwn do not support this release as yet, so DO NOT install 2.2 using iTunes as you will lose your jailbreak